A5085966151- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Pulsars and Gravitational Waves Research
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Stellar, planetary, and galactic studies
- Advanced Differential Geometry Research
- Astrophysical Phenomena and Observations
- Statistical and numerical algorithms
- Statistical Mechanics and Entropy
- Geophysics and Gravity Measurements
- Black Holes and Theoretical Physics
- Noncommutative and Quantum Gravity Theories
- Dark Matter and Cosmic Phenomena
- Astronomical Observations and Instrumentation
- Relativity and Gravitational Theory
- Gaussian Processes and Bayesian Inference
- Solar and Space Plasma Dynamics
- CCD and CMOS Imaging Sensors
- Advanced Chemical Physics Studies
- Adaptive optics and wavefront sensing
- GNSS positioning and interference
- Advanced Research in Science and Engineering
Chongqing University
2015-2024
Fermi National Accelerator Laboratory
2017-2022
Mianyang Normal University
2022
Institute of High Energy Physics
2012-2015
Chinese Academy of Sciences
2012-2015
University of California, Davis
1990-1997
We present angular diameter measurements obtained by measuring the position of Baryon Acoustic Oscillations (BAO) in an optimised sample galaxies from first three years Dark Energy Survey data (DES Y3). The consists 7 million distributed over a footprint 4100 deg$^2$ with $0.6 < z_{\rm photo} 1.1$ and typical redshift uncertainty $0.03(1+z)$. selection is same as BAO measurement year DES data, but analysis presented here uses times area, extends to higher makes number improvements, including...
We present the first cosmological parameter constraints using measurements of type Ia supernovae (SNe Ia) from Dark Energy Survey Supernova Program (DES-SN). The analysis uses a subsample 207 spectroscopically confirmed SNe three years DES-SN, combined with low-redshift sample 122 literature. Our "DES-SN3YR" result these 329 is based on series companion analyses and improvements covering SN discovery, spectroscopic selection, photometry, calibration, distance bias corrections, evaluation...
We investigate the dark matter profile of Milky Way using observed rotation curve data out to 100 kpc. The baryonic is divided into bulge, disk and gas components, each component modelled various possible mass profiles available in literature. arbitrary combination seven bulge profiles, four two results fifty-six baryon models. These models are combined with one profiles: Burkert profile, core-modified pseudo-isothermal NFW fit data. Results show that general fits better than while...
We probe the possible anisotropy of Universe by using JLA compilation type-Ia supernovae. apply Markov Chain Monte Carlo (MCMC) method to constrain amplitude and direction in three cosmological models. For dipole-modulated $\Lambda$CDM model, anisotropic is consistent with zero at $68\%$ C.L., has an upper bound $A_D<1.98\times10^{-3}$ $95\%$ C.L. Regardless much larger uncertainty, we find dipole amazingly opposite that Union2. Similar results are found for $w$CDM CPL Thus, still well...
ABSTRACT We constrain the photon mass from well-localized fast radio bursts (FRBs) using Bayes inference method. The probability distributions of dispersion measures (DMs) host galaxy and intergalactic medium are properly taken into account. is tightly constrained 17 FRBs in redshift range 0 &lt; z 0.66. Assuming that there no evolution DM, 1σ 2σ upper limits to be mγ 4.8 × 10−51 kg 7.1 kg, respectively. Monte Carlo simulations show even enlarging FRB sample 200 extending 3 could not...
Abstract In this paper, we investigate the fast radio burst (FRB) population using first CHIME/FRB catalog. We reconstruct extragalactic dispersion measure–redshift relation (DM E – z relation) from well-localized FRBs, then use it to infer redshift and isotropic energy of The intrinsic distribution is modeled by power law with an exponential cutoff, selection effect CHIME telescope a two-parametric function specific fluence. For distribution, star formation history (SFH) model five other...
We use two different methods, i.e., dipole-fitting (DF) and hemisphere comparison (HC), to search for the anisotropic signals hiding in Union2.1 data set.We find that directions of maximum matter density derived using these methods are about 114 • away from each other.We construct four Union2.1-likemock samples test statistical significance methods.It is shown DF method statistically significant, while HC strongly biased by distribution points sky.Then we assume anisotropy distance modulus...
We demonstrate that highly accurate joint redshift-stellar mass probability distribution functions (PDFs) can be obtained using the Random Forest (RF) machine learning (ML) algorithm, even with few photometric bands available. As an example, we use Dark Energy Survey (DES), combined COSMOS2015 catalogue for redshifts and stellar masses. build two ML models: one containing deep photometry in $griz$ bands, second reflecting scatter present main DES survey, carefully constructed representative...
Gamma-ray bursts (GRBs) are luminous enough to be detectable up redshift $z\sim 10$. They often proposed as complementary tools type-Ia supernovae (SNe Ia) in tracing the Hubble diagram of Universe. The distance calibrations GRBs usually make use one or some empirical luminosity correlations, such $\tau_{\rm lag}-L$, $V-L$, $E_p-L$, $E_p-E_{\gamma}$, RT}-L$ and $E_p-E_{\rm iso}$ relations. These calibrating methods based on underling assumption that correlations universal over all range. In...
We describe the photometric data set assembled from full six years of observations by Dark Energy Survey (DES) in support static-sky cosmology analyses. DES Y6 Gold is a curated derived Data Release 2 (DR2) that incorporates improved measurement, calibration, object classification and value added information. comprises nearly $5000~{\rm deg}^2$ $grizY$ imaging south Galactic cap includes 669 million objects with depth $i_{AB} \sim 23.4$ mag at S/N $\sim 10$ for extended top-of-the-atmosphere...
Type-Ia supernovae (SNe Ia) are often used as the standard candles to probe anisotropic expansion of Universe. In this paper, we make a comprehensive comparison between hemisphere (HC) method and dipole-fitting (DF) in searching for cosmological preferred direction using Union2 dataset, compilation 557 well-calibrated SNe Ia. We find that directions faintest Ia derived from these two methods approximately opposite. Monte Carlo simulations show results HC strongly depend on distribution data...
Recent released Planck data and other astronomical observations show that the universe may be anisotropic on large scales. Inspired by this, cosmological models have been proposed. We note Finsler-Randers spacetime provides an appropriate framework for cosmology. By adding arbitrary 1-form to Friedmann-Robertson-Walker (FRW) line element, a privileged axis in is picked out. The distance-redshift relation modified direction-dependent. wish model tested crossly independent observations....
We propose a Finsler spacetime scenario of the anisotropic universe. The Finslerian universe requires both fine-structure constant and accelerating cosmic expansion have dipole structure, directions these two dipoles are same. Our numerical results show that direction SnIa Hubble diagram locates at $(l,b)=(314.6^\circ\pm20.3^\circ,-11.5^\circ\pm12.1^\circ)$ with magnitude $B=(-3.60\pm1.66)\times10^{-2}$. And $(l,b)=(333.2^\circ\pm8.8^\circ,-12.7^\circ\pm6.3^\circ)$...
The cosmic distance duality relation (DDR), which connects the angular diameter and luminosity through a simple formula $D_A(z)(1+z)^2/D_L(z)\equiv1$, is an important in cosmology. Therefore, testing validity of DDR great importance. In this paper, we test possible violation using available local data including type Ia supernovae (SNe Ia), galaxy clusters baryon acoustic oscillations (BAO). We write modified as $D_A(z)(1+z)^2/D_L(z)=\eta(z)$, consider two different parameterizations...
Recently, an anisotropic cosmological model was proposed. An arbitrary 1-form, which picks out a privileged axis in the universe, added to Friedmann-Robertson-Walker line element. The distance-redshift relation modified such that it is direction dependent. In this paper, we use Union2 dataset and 59 high-redshift gamma-ray bursts give constraints on anisotropy of universe. results show magnitude about $D=-0.044\pm0.018$, points towards $(l_0,b_0)=(306.1^{\circ}\pm...
We use simulated strongly lensed gravitational wave events from the Einstein telescope to demonstrate how luminosity and angular diameter distances, ${d}_{L}(z)$ ${d}_{A}(z)$, respectively, can be combined test in a model independent manner for deviations cosmic distance duality relation standard cosmological model. In particular, we two machine learning approaches, genetic algorithms Gaussian processes, reconstruct mock data show that both approaches are capable of correctly recovering...
Gamma-ray bursts (GRBs) detected at high redshift can be used to trace the Hubble diagram of Universe. However, distance calibration GRBs is not as easily that type Ia supernovae (SNe Ia). For calibrating method based on empirical luminosity correlations, there an underlying assumption correlations should universal over whole range. In this paper, we investigate possible dependence six with a completely model-independent deep learning method. We construct network combining Recurrent Neural...
We test the possible deviation of cosmic distance duality relation $D_A(z)(1+z)^2/D_L(z)\equiv 1$ using standard candles/rulers in a fully model-independent manner. Type-Ia supernovae are used as candles to derive luminosity $D_L(z)$, and ultra-compact radio sources rulers obtain angular diameter $D_A(z)$. write $D_A(z)(1+z)^2/D_L(z)=\eta(z)$. Specifically, we use two parameterizations $\eta(z)$, i.e. $\eta_1(z)=1+\eta_0 z$ $\eta_2(z)=1+\eta_0 z/(1+z)$. The parameter $\eta_0$ is obtained...
In quantum gravity, a foamy structure of space-time leads to Lorentz invariance violation (LIV). As the most energetic astrophysical processes in Universe, gamma-ray bursts (GRBs) provide an effective way probe gravity effects. We use continuous spectra 20 short GRBs detected by Swift satellite give conservative lower limit energy scale $M_\textrm{QG} $. Due LIV effect, photons with different have velocities. This will lead delayed arrival high relative low ones. Based on fact that...
We reconstruct the extragalactic dispersion measure \ -- redshift relation (${\rm DM_E}-z$ relation) from well-localized fast radio bursts (FRBs) using Bayesian inference method. Then ${\rm is used to infer and energy of first CHIME/FRB catalog. find that distributions inferred non-repeating CHIME/FRBs follow cut-off power law, but with a significant excess at low-redshift range. apply set criteria exclude events which are susceptible selection effect, low still exists in remaining FRBs...
The effective potential in the Grumiller's modified gravity includes Newtonian and a Rindler term. fitting to rotation curve data of eight galaxies suggests universal acceleration ≈ 0.30 × 10−10 m s−2. We do two-parameter fit first, with mass-to-light ratio (ϒ*) (a) as free parameters. It is found that six out well prediction theory range 0 ≲ r 40 kpc, although theoretical curves show tendency arising beyond this range. accelerations well-fitted have same magnitude, an average value...
It is known that theory of MOND with spherical symmetry cannot account for the convergence κ-map Bullet Cluster 1E0657-558.In this paper, we try to set up a Finslerian MOND, generalization in Finsler spacetime.We use Ric = 0 obtain gravitational vacuum field equation four-dimensional spacetime.To leading order post-Newtonian approximation, explicit form line element.It simply Schwarzschild's metric except rescaling coefficient f (v) radial coordinate r, i.e.R (v(r))r.By setting (v(r)) (1 -a...
Gamma-ray bursts (GRBs) are widely proposed as an effective probe to trace the Hubble diagram of Universe in high redshift range. However, calibration GRBs is not easy that type-Ia supernovae (SNe Ia). Most calibrating methods at present make use one or some empirical luminosity correlations, e.g., Amati relation. One underlying assumptions these correlation universal over all redshifts. In this paper, we check what extent assumption holds. Assuming SNe Ia exactly Universe, re-investigate...
The equation of state (EoS) dark energy plays an important role in the evolution universe and arouses great interests recent years. With progress on observational technique, precise constraint EoS becomes possible. In this paper, we reconstruct cosmic expansion using Gaussian processes (GP) from most up-to-date Pantheon compilation type Ia supernovae (SNe Ia), which consists 1048 finely calibrated SNe Ia. reconstructed has large uncertainty due to its dependence second order derivative...